The present invention relates to a safety hypodermic syringe, and more particularly to such a safety hypodermic syringe, which has a detachable plunger that can be disconnected from the syringe barrel after the service of the syringe.
Various functional safety hypodermic syringes have been well known. These safety hypodermic syringes are made for enabling the user to pull the needle assembly backwards to the inside of the syringe barrel after injection, preventing possible contamination. However, all parts of conventional safety hypodermic syringes must be thrown away after their use, i.e., neither part of used safety hypodermic syringes can be recycled.
The invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a safety hypodermic syringe, which enables the plunger to be disconnected from the syringe barrel for recycling after the service of the hypodermic syringe and after the needle assembly has been received inside the syringe barrel. According to the present invention, the safety hypodermis syringe is comprised of a barrel, needle assembly, and a plunger assembly. The needle assembly has a coupling means at the rear side of the needle hub thereof. The plunger assembly comprises a stopper holder holding a stopper, and a plunger connected to the rear side of the stopper holder. The stopper holder has front coupling means coupled to the coupling means of the needle assembly, and a rear coupling means. The plunger has a coupling means at the front side thereof coupled to the rear coupling means of the stopper holder for enabling the needle assembly and the stopper holder with the stopper to be moved backwards and received inside the barrel upon back stroke of the plunger after the service of the syringe to prevent possible contamination. After back stroke of the plunger, the plunger can be disconnected from the stopper holder and removed out of the barrel for recycling.